The invention relates to a lock cylinder. More particularly, the invention relates to a lock cylinder which employs pins which must fall in order for the lock to open.
Most common key locks employ a stator and a rotor. The stator is stationary with respect to the door, and the rotor is capable of rotation in a bore extending through the stator. In such a lock the rotor must rotate in order to unlatch, and thus unlock the lock. However, the rotor is prevented from moving without a properly coded key.
The particular manner in which the rotor is normally prevented from moving, and is selectively allowed to rotate with the correct key, is the subject of this invention. In most typical locks, a series of pins extend in the stator parallel to the keyway, and are spring biased toward the rotor. The pins extend between the stator and rotor, and thus prevent the rotation of the rotor. Secondary pins or varying lengths extend in the rotor adjacent to the keyway. When a key having the proper contours is inserted into the keyway, the contours correspond with the secondary pins, which push the primary pins just far enough to clear the rotor, and to allow the rotor to rotate and unlock the lock.
The problem with the standard lock as described, is that it is relatively easy to "pick". The actual phrase "picking a lock" derives from the fact that a fine metal wire, or "pick" is inserted into the keyway to push the secondary pins upward until the lock opens.
Many techniques have been employed to try to make locks "pick proof". However, these techniques are relatively unsuccessful, because they still employ the same basic lock technology as described above.
While these units may be suitable for the particular purpose employed, or for general use, they would not be as suitable for the purposes of the present invention as disclosed hereafter.